A solution of urea contains 8.6 gm/litre (mol. Wt. 60.0). It is isotonic with

Discussion Forum : Solutions

Question -

A solution of urea contains 8.6 gm/litre (mol. Wt. 60.0). It is isotonic with a 5% (W/W) solution of a non-volatile solute having density 1 g/cc. The molecular weight of the solute will be

Options:

A . 348.8

B . 34.88

C . 3488

D . 861.2

Answer: Option A
:
A

Isotonic solutions have same osmotic pressure
As Osmotic pressure = C R T
$\Rightarrow C_{1} = C_{2}$
$\Rightarrow \frac{n_{1}}{V_{1}} = \frac{n_{2}}{V_{2}}$
$5 %$ W/W solution means 100g of solution contains 5 g of solute
$∴ \frac{\frac{8.6}{60}}{1} = \frac{\frac{5}{M}}{\frac{100}{1000}}$
$\Rightarrow M = \frac{5 \times 60 \times 10}{8.6} = 348.8$

Was this answer helpful ?

Next Question

Discussion Forum : Solutions

Submit Your Solution hear: